Typewriting-machine



W. F. HELMOND.

TYPEWRITING MACHINE.

APPLICATION FILED APR. I8. m9.

4 Patented Jan. 4, 1921.

UNITED STATES PATENT oF ica.

WILLIAM I. I-IELMOND, OF HARTFORD, CONNECTICUT, ASSIGNOR TO UNDER/WOOD TYPEWRITER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELA- WARE.

TYPEWRITING-MACHINE.

Specification of Letters Patent.

Patented Jan. 4, 1921.

Application filed April 18, 1919. Serial No. 290,965.

T 0 all whom it may concern:

Be it known that I, 'WVILLIAM F. HELMOND, a citizen of the United States, residing in Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Typewriting-Machines, of which the following is a specification.

This invention relates to the slotted typeguides in writing machines of the Underwood class.

Heretofore, the guide has comprised a flaring directrix terminating in a slot fitting the type-bar, to insure accuracy of printing. The directrix has been V-shaped, with straight converging sides, making corners where the converging sides met the parallel sides of the guide slot.

The type-bars move at high speed when entering the guide, and owing to their thinness are apt to spring sidewise, so that upon striking one of the straight sides of the V guide, the type-bar is apt to be sprung laterally over against the opposite side of the V, or to strike its corner. This is an objection, partly on account of the noise, and partly because it tends to retard the typebar, as well as to wear the same.

An object of the invention, therefore, is to improve the type-guide with a view to mini mizing or eliminating the noise and facilitating the entrance of the type-bar into the narrow guiding slot or throat, thus conduc-' ing to higher speed of operation and increased accuracy of printing and durability of the type-bar.

To these ends, each of the sides of the directrix is formed on a single convex curve, the curves continuing to form or merge into the inner end of the guide, which fits the type-bar. Therefore no corner is presented, to form an obstruction to be struck sharply by the type-bar. The curvature is such as to minimize liability of sidewise springing of the type-bar when contacting with the same; the divergence of the sides of the directrix being greatest at the forward end thereof, and being gradually reduced to merge into the parallel sided guide slot. Thus, the type-bar can contact only with a convex surface, and can give it only a glancing blow, resulting in little or no lateral spring or rebound, and therefore producing no more than a mere sliding action of the type-bar against the opposite wall of the directrlx, whereby the speed of the type-bar is not retarded, and noise is largely reduced.

In said Underwood typewriter, the ty egulde 1s usually formed upon the top of a shank or standard, which is split vertically for convenlence in effecting relative adjustment of the jaws of the guide; and it is one of the objects of the invention to overcome the difficulty presented by the necessit of formlng the convexly curved guide sur aces upon a t ne-guide which is integral with its shank. he formation of the curved guiding surfaces is effected by the use of a crownmlllmg cutter, which cuts down into the head of the blank, forming an arc-shaped cut, thereby producing one wall of the typeguide, and by then using the cutter to cut down into the head, to form the opposite curved wall of the type-guide, at the same time finishing the cutting out of the waste trlangular portion of the blank.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a perspective front view of the platen and platen frame of an Underwood typewriting machine, with the typeguide and ribbon-vibrator in front thereof.

Figs. 2 and 3 are plans to show the operations of forming the type-guiding surfaces.

Fig. 4 is a plan of the completed guide.

Fig. 5 illustrates a manner of surfacefinishing the curved faces of the guide.

Fig. 6 is a plan, illustrating the upper portion of a type-bar fitting in the slot ofthe guide.

Fig. 7 is a perspective view of the completed guide.

Types 10, upon the ends of pivoted bars 11, strike rearwardly through the typeguide and a ribbon 12, against a platen 13, journaled in platen frame 14, as usual in the Underwood typewriter.

The improved type-guide or directrix comprises opposite guiding cheeks or surfaces 15, 16, formed upon jaws 17, 18, which are formed upon the upper end of a shank 19, rising from a base 20, by which thetypeguide is secured to the ordinary type-bar segment or frame 21. The shank is split vertically and centrally at 22, and is bored and tapped to receive a conical expanding screw 23, whereby the jaws 17 and 18 may be separated, thus affording a slight relative adjustment.

The type-guiding surfaces 15 and 16 are convexly curved, having the greatest flare at their outer ends, the flare becoming less and less until the jaws are approximately parallel at their inner ends. Because of the curvature, the sidewise blow of the type-bar is rendered more glancing than with the old straight-sided .jaws, and hence the typebar contacting with either jaw is not thrown over so violently against the other jaw as in previous guides. Moreover, upon striking the other jaw it makes only a glancing blow. Hence the sidewise vibration of the type-bar is not so violent as heretofore, and inflicts less injury upon the type-bar and the guide. The guide is also less noisy, particularly because of the absence of a defined corner on either jaw with which the typebar may collide. The device has proven easy in operation and highly satisfactory.

ince it is desirable to form said jaws and the shank 19 integral, in order that the described relative adjustment of the jaws may be provided for, and since a difliculty is presented in machining the desired contour upon the jaws, I have devised the method of accomplishing this which is illustrated in Figs. 2 and 3. The jaw blank 24 is milled by a crown-milling cutter 25, which mills its way down into the head of the blank, and entirely through the head, and produces thereon the desired contour 15, thereby completing one of the jaws. Then the other side of the milling cutter device may be employed, in a similar manner, to form the opposite convex surface 16, and at the same time finishing the cutting out of the waste triangular piece between the jaws. It will be seen that the arc of each jaw is struck from a point 26 which is at one side of the jaw and opposite the' place 27 where the jaws are closest together, thereby giving the desired convex contour for causing the blows of the type-bars to be glancin and also giving ample flare at the front 0 the guide.

To give the desired smoothness and hard finish to the type-guiding surfaces of the jaws, they are preferably subjected to a pressing or hammering o eration, and for this purpose the type-gui e may be set into a fixture comprising a tapering anvil 28 which fits between the jaws. The latter ma then be pressed or hammered toward eac other, as indicated by the horizontal arrows 1n Fig. 5. Or the fixture may hold the jaws firmly while the part 28 may be used as a press or hammer, striking up in the direction of the vertical arrow at Fig. 5. The hammering or pressing operation may be continued until the desired smooth, hard surface is produced; and then the jaws may also be su jected to any suitable case-hardening or other hardening and finishing treatment.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be' used without others.

Having thus described my invention, I claim: a

l. A one-piece type-guide comprising a pair of opposed jaws made from a single blank, said jaws having inwardly disposedcurved type-guiding surfaces cut to conform in outline with arcs of circles of relatively great radii compared with the lengths of such jaws, said arcs being struck from cen: ters lying at o posite sides of said jaws in a line passing t erethrough forward of their rear extremities, said curved surfaces thus forming flaring walls which gradually approach each other from their forward extremities rearwardly to form a type-positioning throat therebetween, at and near the points where said arcs are intersected by the line joining said centers.

2. A one-piece type-guide comprising a pair of opposed jaws made from a single blank, said jaws having inwardlydisposed curved typeuiding surfaces cut and pressed or bllI'IllShGCT to.finished guiding faces to conform inoutline with arcs of circles of relatively great radii compared with the lengths of such jaws, said arcs being struck from centers lying at opposite sides of said jaws in a line passing therethrough forward of their rear extremities, said curved surfaces thus forming flaring wallswhich gradually approach each other from their forward extremities rearwardly to form a typepositioning throat therebetween, at and near the points where said arcs are intersected by the line joining said centers.

3. The method of forming the described type-guide, comprising cutting down into a jaw blank with a crown-milling cutter to form one of the type-guiding jaws, and then cutting down into the blank with a crownmillin cutter to form the other convex jaw.

4. The method of forming the descrlbed type-guide, comprising cutting down into a jaw blank with a crown-milling cutter .to form one of the type-guiding jaws, and then cutting down into the blank with a crownmilling cutter to form the other convex jaw, and subjecting the convex jaws to a compressing or hammering action to finish the type-guiding surfaces thereon.

5. I one-piece type-guide comprising a pair of opposed jaws made from a single blank, said jaws having inwardly disposed curved type-guiding surfaces cut to concenters lying at opposite sides of said jaws in a line passing through the same slightly forward of their rear extremities, said curved surfaces thus forming flaring walls which gradually approach each other from their forward extremities rearwardly to form a type-positioning throat therebetween, at and near the points where said arcs are intersected by the line joining said centers, each of said surfaces being continued in the form .of a circular arc rearwardly of said throat to the rear extremity of the respective jaw of which it is a part. i

6. The method of forming a type-guide of the character herein described, which consists in first cutting into a jaw blank with a crown-milling cutter to form the convex surface of a type-guide jaw, then cutting 15 into another part of said blank with a crownmilling cutter to form the convex surface of the other type-guide jaw, then insertin an anvil or former between the convex sur aces of said jaws, and then subjecting said jaws and former to a compressing or hammering action, to bring them into intimate contact, and thus finish the type-guiding surfaces.

WILLIAM F. HELMOND.

WVitnesses:

SHIRLEY E. GLEDHILL, WILLIAM P. SMITH. 

